OFDM signal down frequency conversion based on a SOA-MZI sampling mixer using differential modulation and switching architectures

Abstract

Abstract A simulation performance analysis of a semiconductor optical amplifier Mach–Zehnder interferometer (SOA-MZI) sampling mixer used as a frequency down converter is presented by employing differential modulation and switching architectures. A clock pulse signal, generating 2 ps-width pulses at a sampling frequency of 13\xa0GHz, is used as a sampling signal. Two optical carriers, intensity-modulated by a sinusoidal signal at 79 and 80\xa0GHz are simultaneously down converted to 1 and 2\xa0GHz, respectively. For the differential modulation architecture, conversion gains of about 34 and 32\xa0dB are demonstrated for the frequency down conversion to 1 and 2\xa0GHz, respectively. Besides, the conversion gain of 20 dB is achieved for down conversion from 79 to 1\xa0GHz for the differential switching architecture. Furthermore, signals modulated by an orthogonal frequency division multiplexing (OFDM) complex modulation format at different bit rates are also down converted from 79 to 1\xa0GHz and from 80 to 2\xa0GHz and their error vector magnitude (EVM) is evaluated and compared. A maximum bit rate of about 8 Gbps satisfying the forward error correction (FEC) limit is fulfilled using differential modulation and switching architectures.